Short answer. No, that clause is void and you can disregard it. Article 874 of the Civil Code states that an absolute condition not to contract a first or subsequent marriage shall be considered as not written. The inheritance passes to you without the restriction, because the law refuses to enforce a blanket prohibition on your right to marry.
What the law says
An absolute condition not to contract a first or subsequent marriage shall be considered as not written
Civil Code, Article 874 — Conditions About Marrying. Read the full provision →
The clause in your father's will is void
Article 874 is clear: an absolute condition not to contract a first or subsequent marriage shall be considered as not written. This means the clause is simply erased from the will. It does not affect the bequest itself — you receive the inheritance — but the forfeiture condition attached to it has no legal force. You are free to marry without losing what was left to you. A testator, regardless of how strongly he felt about his children's personal choices, cannot use the will to extinguish a person's right to marry.
Why the law treats this condition as void
The right to marry is a fundamental personal freedom. Conditioning an inheritance on never marrying is treated as contrary to public policy because it weaponises economic dependence to control who a person may or may not choose as a spouse. The Civil Code resolves this by declaring the condition unwritten — not by voiding the entire bequest, but only the restriction. The heir gets the property; the testator's attempt to govern the heir's personal life posthumously does not survive.
The exception: when the condition is imposed by a deceased spouse
Article 874 recognises one limited exception. The prohibition on marrying can be validly imposed on a widow or widower, but only when it is the deceased spouse himself or herself who imposed it — or the deceased's ascendants or descendants. In that narrow setting, the surviving spouse may have agreed, at least implicitly, to a kind of fidelity arrangement that the law respects. But this exception does not apply to you: your father is not your deceased spouse, so the exception has no bearing on a child receiving an inheritance.
Usufruct during widowhood is treated differently
Article 874 also notes that a testator may lawfully grant a usufruct, allowance, or personal prestation to someone for as long as that person remains unmarried or in widowhood. This is different from an absolute condition. It does not prohibit marriage — it simply ends a specific benefit once the person marries. If your father had phrased it that way, the legal effect would be different: you could marry freely, but a specific right of use or periodic benefit from the estate would cease. A blanket forfeiture clause, however, goes beyond this and is struck out by Article 874.